CVE-2026-47684
Sync-in Server: SSRF protection bypass via IPv4-mapped IPv6 addresses in regExpPrivateIP
Description
Summary: The private IP blocklist regex used in the URL download feature does not match IPv4-mapped IPv6 addresses (e.g. ::ffff:127.0.0.1), allowing SSRF protection to be bypassed on dual-stack systems. Affected components backend/src/applications/files/services/files-manager.service.ts – downloadFromUrl() checks regExpPrivateIP against request.socket.remoteAddress. backend/src/applications/files/utils/url-file.ts – regExpPrivateIP does not include ::ffff:<ipv4> variants. Details: The regExpPrivateIP regex in backend/src/applications/files/utils/url-file.ts correctly blocks standard IPv4 private ranges but does not include ::ffff: prefixed variants. On dual-stack systems, Node.js can report a socket's remoteAddress in IPv4-mapped IPv6 form, meaning the check in FilesManager.downloadFromUrl() can be bypassed entirely. PoC: [poc.pdf](https://github.com/user-attachments/files/26990874/poc.pdf) Proof: <img width="1080" height="842" alt="1000226655" src="https://github.com/user-attachments/assets/797cea83-0a08-4a16-a91b-31c51068d473" /> Impact: An attacker can supply a crafted URL pointing to an internal address that gets reported as ::ffff:127.0.0.1 or ::ffff:10.x.x.x, causing the server to fetch internal resources that should be blocked. Any user with access to the file download feature is a potential attacker.
How to fix CVE-2026-47684
To remediate CVE-2026-47684, upgrade the affected package to a fixed version below.
- —upgrade to 2.3.0 or later
Is CVE-2026-47684 being exploited?
No exploitation signal available. Neither CISA KEV nor a current EPSS score has been published for CVE-2026-47684.
Affected packages (1)
- from 0, < 2.3.0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH7.7 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N |